spectre.console/docs/input/appendix/styles.md

Title: Styles Order: 1

Note that what styles that can be used is defined by the system or your terminal software, and may not appear as they should.

bold	Bold text
dim	Dim or faint text
italic	Italic text
underline	Underlined text
invert	Swaps the foreground and background colors
conceal	Hides the text
slowblink	Makes text blink slowly
rapidblink	Makes text blink
strikethrough	Shows text with a horizontal line through the center